Circle Circumference Calculator

Circle Circumference Formulas

Key formulas:

  • Circumference = 2π × radius
  • Circumference = π × diameter
  • Circumference = 2 × √(π × area)
  • Arc Length = (angle/360°) × circumference
  • Arc Length = radius × angle (in radians)

Note: For precise calculations, this calculator uses the mathematical constant π (pi) rather than the approximation 3.14. Enter an angle less than 360° to calculate arc length and percentage.